With the development of high throughput screening
technology in recent years, the acquisition of chemical samples by samples
collection and combinatorial synthesis now become the bottleneck in the
process of new drug discovery.

A new pairwise similarity formula has been defined
and used for molecular diversity assessment based on a novel method. The
logarithmic relations of entropy and similarity give the expected diversity
values which decrease with the increase in species similarities [1,2].

Molecular diversity consists both chemical information
and chemical substances of molecules. Chemists contribute not only new
knowledge but also new substances. However, more than 90% of compounds
recorded in literature exist only on paper; they were discarded by chemists.
The high quality of a chemical library relies on the distinct differences
of both the structures and properties of the collected samples [1,2]. These
compounds in isolated form are traditionally and still routinely prepared
in the laboratories and isolated from natural sources. Among other strategies,
the first chemistry journal Molecules (visit http://www.mdpi.org/molecule/)
was launched in 1995 to encourage authors to deposit their compound samples
at MDPI center in Switzerland of the nonprofit organization MDPI and distribute
free of charge or at reasonable prices worldwide. This samples deposit
and exchange project has been supported by several other international
chemistry journals (visit the website http://www.mdpi.org/forum.htm). The
idea [3] of this program is to supply both chemical information as well
as the chemical substances themselves, and to preserve chemical samples
for drug discovery.

References

1. S.-K. Lin, Molecular Diversity Assessment:
Logarithmic Relations of Information and Species Diversity and Logarithmic
Relations of Entropy and Indistinguishability after Rejection of Gibbs
Paradox of Entropy of Mixing.Molecules1996, 1,
57-67.

3. S.-K. Lin, Guide to the Deposit of and Exchange
of Compound Samples. 212th acs National Meeting, Orlando, Florida,
August 25-29, 1996. See also http://www.mdpi.org/lin/lin-co.htm
for other conference presentations.